908. Is it possible to mechanically connect two motors of equal speeds and powers to provide twice as much power as a single motor? — EG, Torrance, CA
As long as they're both AC induction motors, I don't see any reason why not. While induction motors would turn synchronously with the power line if they had absolutely no load, they naturally lag slightly behind in normal situations. While a line synchronous AC motor would turn at 1800 or 3600 rpm, depending on how it's wired, a typical induction motor turns at 1725 or 3450 rpm. The more you load an induction motor, the slower it turns and the more torque it exerts on that load. By coupling two induction motors together mechanically, you'll make them turn at the same rate. Since the torque each motor exerts on the load depends on rotation speed, they'll both contribute equally to the task and will together provide twice the power of a single motor.
I wouldn't try this with any kind of motor that doesn't have such a clear relationship between rotational speed and power output. If you join two mismatched motors with one another, one may end up doing all the work and the other motor might effectively become a generator rather than a motor!